Description

Returns the decimal digit value of the code point in the specified radix.

If the radix is not in the range 2<=radix<=36 or if the value of codepoint
is not a valid digit in the specified radix, FALSE is returned.
A character is a valid digit if at least one of the following is true:

The character has a decimal digit value. Such characters have the general category "Nd" (decimal digit numbers) and a Numeric_Type of Decimal. In this case the value is the character's decimal digit value.

The character is one of the uppercase Latin letters 'A' through 'Z'. In this case the value is c-'A'+10.

The character is one of the lowercase Latin letters 'a' through 'z'. In this case the value is ch-'a'+10.

Latin letters from both the ASCII range (0061..007A, 0041..005A) as well as from the Fullwidth ASCII range (FF41..FF5A, FF21..FF3A) are recognized.

Parameters

codepoint

The integer codepoint value (e.g. 0x2603 for U+2603 SNOWMAN), or the character encoded as a UTF-8 string (e.g. "\u{2603}")

radix

The radix (defaults to 10).

Return Values

Returns the numeric value represented by the character in the specified radix,
or FALSE if there is no value or if the value exceeds the radix.

Warning

This function may
return Boolean FALSE, but may also return a non-Boolean value which
evaluates to FALSE. Please read the section on Booleans for more
information. Use the ===
operator for testing the return value of this
function.